Protein,nucleic acids and cell structure in the regenerating mouse liver

Summary Prior to the onset of mitotic activity in the regenerating mouse liver, the concentrations of total protein and DNA, but not of RNA, decreased to 93 per cent of their levels in normal liver. During maximum mitosis (48–72 hours), the DNA and RNA concentrations were 110 per cent of their normal levels. The concentrations of liver nucleic acids 24 hours after a sham-operation were also about 110 per cent of normal values.Increased concentrations of insoluble protein were found at 12, 24 and 144 hours after partial hepatectomy. This may reflect an increase in the stability of the liver cell membranes during the regenerative period. Increased amounts of various cytoplasmic membranes were indicated by electronmicroscopy and may also have contributed to the increase in insoluble protein.A temporary increase in the measured solubility of the liver protein occurred during maximum mitosis. It is suggested that this was due to the association of protein with lipids during the depletion of accumulated fat from the regenerating liver.This investigation was facilitated by grants from the Royal. Physiographical Society.I wish to thank Professor I. Agrell and Docent B. Karlsson for helpful advice and criticism and Miss E. K. Persson for skilled technical assistance.